Unsteady Aerodynamics, Dynamic Stall and Dynamic Wake in AeroDyn 15

Discuss the theory and modeling of rotor aerodynamics.

Moderator: Bonnie.Jonkman

Jens.Geisler
Posts: 8
Joined: Fri Jan 17, 2020 7:12 am
Organization: self
Location: Germany

Unsteady Aerodynamics, Dynamic Stall and Dynamic Wake in AeroDyn 15

Postby Jens.Geisler » Mon Jan 27, 2020 10:46 am

Hi,
when I get the warning "Turning off Unsteady Aerodynamics because C_nalpha is 0. BladeNode = 1, Blade = 1", does that mean that only the dynamic stall feature is disabled for that blade and foil section or also the dynamic inflow/wake effect is turned off?

I am asking, because I'm actually looking for a way to turn off only dynamic stall without turning off dynamic wake. Ideally I would even like to selectively turn off dynamic stall only for some foil sections / nodes, e.g. around the blade tip where the foils have very small chord length which, in combination with the high effective inflow speed, leads to extremely small time constants.

If setting C_nalpha to zero does in fact turn off dynamic stall and dynamic wake, are there maybe other parameters that I could use to effectively turn off only dynamic stall?

Jason.Jonkman
Posts: 4617
Joined: Thu Nov 03, 2005 4:38 pm
Location: Boulder, CO
Contact:

Re: Unsteady Aerodynamics, Dynamic Stall and Dynamic Wake in AeroDyn 15

Postby Jason.Jonkman » Mon Jan 27, 2020 12:25 pm

Dear Jens,

Yes, the warning about "turning off unsteady aerodynamics" only applies to the unsteady airfoil aerodynamics (UA, dynamic stall) model; dynamic wake will still be enabled if it was at initialization.

To disable UA at a given airfoil section, you can set C_nalpha = 0 or you can set UACutOut = 0.

Best regards,
Jason Jonkman, Ph.D.
Senior Engineer | National Wind Technology Center (NWTC)

National Renewable Energy Laboratory (NREL)
15013 Denver West Parkway | Golden, CO 80401
+1 (303) 384 – 7026 | Fax: +1 (303) 384 – 6901
nwtc.nrel.gov

Jens.Geisler
Posts: 8
Joined: Fri Jan 17, 2020 7:12 am
Organization: self
Location: Germany

Re: Unsteady Aerodynamics, Dynamic Stall and Dynamic Wake in AeroDyn 15

Postby Jens.Geisler » Mon Jan 27, 2020 11:58 pm

Great, thanks a lot!


Return to “Rotor Aerodynamics”

Who is online

Users browsing this forum: No registered users and 1 guest